2 * Driver for GRLIB serial ports (APBUART)
4 * Based on linux/drivers/serial/amba.c
6 * Copyright (C) 2000 Deep Blue Solutions Ltd.
7 * Copyright (C) 2003 Konrad Eisele <eiselekd@web.de>
8 * Copyright (C) 2006 Daniel Hellstrom <daniel@gaisler.com>, Aeroflex Gaisler AB
9 * Copyright (C) 2008 Gilead Kutnick <kutnickg@zin-tech.com>
10 * Copyright (C) 2009 Kristoffer Glembo <kristoffer@gaisler.com>, Aeroflex Gaisler AB
13 #if defined(CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
17 #include <linux/module.h>
18 #include <linux/tty.h>
19 #include <linux/tty_flip.h>
20 #include <linux/ioport.h>
21 #include <linux/init.h>
22 #include <linux/serial.h>
23 #include <linux/console.h>
24 #include <linux/sysrq.h>
25 #include <linux/kthread.h>
26 #include <linux/device.h>
28 #include <linux/of_device.h>
29 #include <linux/of_platform.h>
30 #include <linux/of_irq.h>
31 #include <linux/platform_device.h>
33 #include <linux/serial_core.h>
38 #define SERIAL_APBUART_MAJOR TTY_MAJOR
39 #define SERIAL_APBUART_MINOR 64
40 #define UART_DUMMY_RSR_RX 0x8000 /* for ignore all read */
42 static void apbuart_tx_chars(struct uart_port *port);
44 static void apbuart_stop_tx(struct uart_port *port)
48 cr = UART_GET_CTRL(port);
50 UART_PUT_CTRL(port, cr);
53 static void apbuart_start_tx(struct uart_port *port)
57 cr = UART_GET_CTRL(port);
59 UART_PUT_CTRL(port, cr);
61 if (UART_GET_STATUS(port) & UART_STATUS_THE)
62 apbuart_tx_chars(port);
65 static void apbuart_stop_rx(struct uart_port *port)
69 cr = UART_GET_CTRL(port);
70 cr &= ~(UART_CTRL_RI);
71 UART_PUT_CTRL(port, cr);
74 static void apbuart_enable_ms(struct uart_port *port)
76 /* No modem status change interrupts for APBUART */
79 static void apbuart_rx_chars(struct uart_port *port)
81 struct tty_struct *tty = port->state->port.tty;
82 unsigned int status, ch, rsr, flag;
83 unsigned int max_chars = port->fifosize;
85 status = UART_GET_STATUS(port);
87 while (UART_RX_DATA(status) && (max_chars--)) {
89 ch = UART_GET_CHAR(port);
94 rsr = UART_GET_STATUS(port) | UART_DUMMY_RSR_RX;
95 UART_PUT_STATUS(port, 0);
96 if (rsr & UART_STATUS_ERR) {
98 if (rsr & UART_STATUS_BR) {
99 rsr &= ~(UART_STATUS_FE | UART_STATUS_PE);
101 if (uart_handle_break(port))
103 } else if (rsr & UART_STATUS_PE) {
104 port->icount.parity++;
105 } else if (rsr & UART_STATUS_FE) {
106 port->icount.frame++;
108 if (rsr & UART_STATUS_OE)
109 port->icount.overrun++;
111 rsr &= port->read_status_mask;
113 if (rsr & UART_STATUS_PE)
115 else if (rsr & UART_STATUS_FE)
119 if (uart_handle_sysrq_char(port, ch))
122 uart_insert_char(port, rsr, UART_STATUS_OE, ch, flag);
126 status = UART_GET_STATUS(port);
129 tty_flip_buffer_push(tty);
132 static void apbuart_tx_chars(struct uart_port *port)
134 struct circ_buf *xmit = &port->state->xmit;
138 UART_PUT_CHAR(port, port->x_char);
144 if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
145 apbuart_stop_tx(port);
149 /* amba: fill FIFO */
150 count = port->fifosize >> 1;
152 UART_PUT_CHAR(port, xmit->buf[xmit->tail]);
153 xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
155 if (uart_circ_empty(xmit))
157 } while (--count > 0);
159 if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
160 uart_write_wakeup(port);
162 if (uart_circ_empty(xmit))
163 apbuart_stop_tx(port);
166 static irqreturn_t apbuart_int(int irq, void *dev_id)
168 struct uart_port *port = dev_id;
171 spin_lock(&port->lock);
173 status = UART_GET_STATUS(port);
174 if (status & UART_STATUS_DR)
175 apbuart_rx_chars(port);
176 if (status & UART_STATUS_THE)
177 apbuart_tx_chars(port);
179 spin_unlock(&port->lock);
184 static unsigned int apbuart_tx_empty(struct uart_port *port)
186 unsigned int status = UART_GET_STATUS(port);
187 return status & UART_STATUS_THE ? TIOCSER_TEMT : 0;
190 static unsigned int apbuart_get_mctrl(struct uart_port *port)
192 /* The GRLIB APBUART handles flow control in hardware */
193 return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
196 static void apbuart_set_mctrl(struct uart_port *port, unsigned int mctrl)
198 /* The GRLIB APBUART handles flow control in hardware */
201 static void apbuart_break_ctl(struct uart_port *port, int break_state)
203 /* We don't support sending break */
206 static int apbuart_startup(struct uart_port *port)
211 /* Allocate the IRQ */
212 retval = request_irq(port->irq, apbuart_int, 0, "apbuart", port);
216 /* Finally, enable interrupts */
217 cr = UART_GET_CTRL(port);
219 cr | UART_CTRL_RE | UART_CTRL_TE |
220 UART_CTRL_RI | UART_CTRL_TI);
225 static void apbuart_shutdown(struct uart_port *port)
229 /* disable all interrupts, disable the port */
230 cr = UART_GET_CTRL(port);
232 cr & ~(UART_CTRL_RE | UART_CTRL_TE |
233 UART_CTRL_RI | UART_CTRL_TI));
235 /* Free the interrupt */
236 free_irq(port->irq, port);
239 static void apbuart_set_termios(struct uart_port *port,
240 struct ktermios *termios, struct ktermios *old)
244 unsigned int baud, quot;
246 /* Ask the core to calculate the divisor for us. */
247 baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
249 panic("invalid baudrate %i\n", port->uartclk / 16);
251 /* uart_get_divisor calc a *16 uart freq, apbuart is *8 */
252 quot = (uart_get_divisor(port, baud)) * 2;
253 cr = UART_GET_CTRL(port);
254 cr &= ~(UART_CTRL_PE | UART_CTRL_PS);
256 if (termios->c_cflag & PARENB) {
258 if ((termios->c_cflag & PARODD))
262 /* Enable flow control. */
263 if (termios->c_cflag & CRTSCTS)
266 spin_lock_irqsave(&port->lock, flags);
268 /* Update the per-port timeout. */
269 uart_update_timeout(port, termios->c_cflag, baud);
271 port->read_status_mask = UART_STATUS_OE;
272 if (termios->c_iflag & INPCK)
273 port->read_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
275 /* Characters to ignore */
276 port->ignore_status_mask = 0;
277 if (termios->c_iflag & IGNPAR)
278 port->ignore_status_mask |= UART_STATUS_FE | UART_STATUS_PE;
280 /* Ignore all characters if CREAD is not set. */
281 if ((termios->c_cflag & CREAD) == 0)
282 port->ignore_status_mask |= UART_DUMMY_RSR_RX;
286 UART_PUT_SCAL(port, quot);
287 UART_PUT_CTRL(port, cr);
289 spin_unlock_irqrestore(&port->lock, flags);
292 static const char *apbuart_type(struct uart_port *port)
294 return port->type == PORT_APBUART ? "GRLIB/APBUART" : NULL;
297 static void apbuart_release_port(struct uart_port *port)
299 release_mem_region(port->mapbase, 0x100);
302 static int apbuart_request_port(struct uart_port *port)
304 return request_mem_region(port->mapbase, 0x100, "grlib-apbuart")
305 != NULL ? 0 : -EBUSY;
309 /* Configure/autoconfigure the port */
310 static void apbuart_config_port(struct uart_port *port, int flags)
312 if (flags & UART_CONFIG_TYPE) {
313 port->type = PORT_APBUART;
314 apbuart_request_port(port);
318 /* Verify the new serial_struct (for TIOCSSERIAL) */
319 static int apbuart_verify_port(struct uart_port *port,
320 struct serial_struct *ser)
323 if (ser->type != PORT_UNKNOWN && ser->type != PORT_APBUART)
325 if (ser->irq < 0 || ser->irq >= NR_IRQS)
327 if (ser->baud_base < 9600)
332 static struct uart_ops grlib_apbuart_ops = {
333 .tx_empty = apbuart_tx_empty,
334 .set_mctrl = apbuart_set_mctrl,
335 .get_mctrl = apbuart_get_mctrl,
336 .stop_tx = apbuart_stop_tx,
337 .start_tx = apbuart_start_tx,
338 .stop_rx = apbuart_stop_rx,
339 .enable_ms = apbuart_enable_ms,
340 .break_ctl = apbuart_break_ctl,
341 .startup = apbuart_startup,
342 .shutdown = apbuart_shutdown,
343 .set_termios = apbuart_set_termios,
344 .type = apbuart_type,
345 .release_port = apbuart_release_port,
346 .request_port = apbuart_request_port,
347 .config_port = apbuart_config_port,
348 .verify_port = apbuart_verify_port,
351 static struct uart_port grlib_apbuart_ports[UART_NR];
352 static struct device_node *grlib_apbuart_nodes[UART_NR];
354 static int apbuart_scan_fifo_size(struct uart_port *port, int portnumber)
361 ctrl = UART_GET_CTRL(port);
364 * Enable the transceiver and wait for it to be ready to send data.
365 * Clear interrupts so that this process will not be externally
366 * interrupted in the middle (which can cause the transceiver to
367 * drain prematurely).
370 local_irq_save(flags);
372 UART_PUT_CTRL(port, ctrl | UART_CTRL_TE);
374 while (!UART_TX_READY(UART_GET_STATUS(port)))
378 * Disable the transceiver so data isn't actually sent during the
382 UART_PUT_CTRL(port, ctrl & ~(UART_CTRL_TE));
385 UART_PUT_CHAR(port, 0);
388 * So long as transmitting a character increments the tranceivier FIFO
389 * length the FIFO must be at least that big. These bytes will
390 * automatically drain off of the FIFO.
393 status = UART_GET_STATUS(port);
394 while (((status >> 20) & 0x3F) == fifosize) {
396 UART_PUT_CHAR(port, 0);
397 status = UART_GET_STATUS(port);
402 UART_PUT_CTRL(port, ctrl);
403 local_irq_restore(flags);
411 static void apbuart_flush_fifo(struct uart_port *port)
415 for (i = 0; i < port->fifosize; i++)
420 /* ======================================================================== */
421 /* Console driver, if enabled */
422 /* ======================================================================== */
424 #ifdef CONFIG_SERIAL_GRLIB_GAISLER_APBUART_CONSOLE
426 static void apbuart_console_putchar(struct uart_port *port, int ch)
430 status = UART_GET_STATUS(port);
431 } while (!UART_TX_READY(status));
432 UART_PUT_CHAR(port, ch);
436 apbuart_console_write(struct console *co, const char *s, unsigned int count)
438 struct uart_port *port = &grlib_apbuart_ports[co->index];
439 unsigned int status, old_cr, new_cr;
441 /* First save the CR then disable the interrupts */
442 old_cr = UART_GET_CTRL(port);
443 new_cr = old_cr & ~(UART_CTRL_RI | UART_CTRL_TI);
444 UART_PUT_CTRL(port, new_cr);
446 uart_console_write(port, s, count, apbuart_console_putchar);
449 * Finally, wait for transmitter to become empty
450 * and restore the TCR
453 status = UART_GET_STATUS(port);
454 } while (!UART_TX_READY(status));
455 UART_PUT_CTRL(port, old_cr);
459 apbuart_console_get_options(struct uart_port *port, int *baud,
460 int *parity, int *bits)
462 if (UART_GET_CTRL(port) & (UART_CTRL_RE | UART_CTRL_TE)) {
464 unsigned int quot, status;
465 status = UART_GET_STATUS(port);
468 if (status & UART_CTRL_PE) {
469 if ((status & UART_CTRL_PS) == 0)
476 quot = UART_GET_SCAL(port) / 8;
477 *baud = port->uartclk / (16 * (quot + 1));
481 static int __init apbuart_console_setup(struct console *co, char *options)
483 struct uart_port *port;
489 pr_debug("apbuart_console_setup co=%p, co->index=%i, options=%s\n",
490 co, co->index, options);
493 * Check whether an invalid uart number has been specified, and
494 * if so, search for the first available port that does have
497 if (co->index >= grlib_apbuart_port_nr)
500 port = &grlib_apbuart_ports[co->index];
502 spin_lock_init(&port->lock);
505 uart_parse_options(options, &baud, &parity, &bits, &flow);
507 apbuart_console_get_options(port, &baud, &parity, &bits);
509 return uart_set_options(port, co, baud, parity, bits, flow);
512 static struct uart_driver grlib_apbuart_driver;
514 static struct console grlib_apbuart_console = {
516 .write = apbuart_console_write,
517 .device = uart_console_device,
518 .setup = apbuart_console_setup,
519 .flags = CON_PRINTBUFFER,
521 .data = &grlib_apbuart_driver,
525 static int grlib_apbuart_configure(void);
527 static int __init apbuart_console_init(void)
529 if (grlib_apbuart_configure())
531 register_console(&grlib_apbuart_console);
535 console_initcall(apbuart_console_init);
537 #define APBUART_CONSOLE (&grlib_apbuart_console)
539 #define APBUART_CONSOLE NULL
542 static struct uart_driver grlib_apbuart_driver = {
543 .owner = THIS_MODULE,
544 .driver_name = "serial",
546 .major = SERIAL_APBUART_MAJOR,
547 .minor = SERIAL_APBUART_MINOR,
549 .cons = APBUART_CONSOLE,
553 /* ======================================================================== */
554 /* OF Platform Driver */
555 /* ======================================================================== */
557 static int __devinit apbuart_probe(struct platform_device *op)
560 struct uart_port *port = NULL;
562 for (i = 0; i < grlib_apbuart_port_nr; i++) {
563 if (op->dev.of_node == grlib_apbuart_nodes[i])
567 port = &grlib_apbuart_ports[i];
568 port->dev = &op->dev;
569 port->irq = op->archdata.irqs[0];
571 uart_add_one_port(&grlib_apbuart_driver, (struct uart_port *) port);
573 apbuart_flush_fifo((struct uart_port *) port);
575 printk(KERN_INFO "grlib-apbuart at 0x%llx, irq %d\n",
576 (unsigned long long) port->mapbase, port->irq);
580 static struct of_device_id __initdata apbuart_match[] = {
582 .name = "GAISLER_APBUART",
590 static struct platform_driver grlib_apbuart_of_driver = {
591 .probe = apbuart_probe,
593 .owner = THIS_MODULE,
594 .name = "grlib-apbuart",
595 .of_match_table = apbuart_match,
600 static int grlib_apbuart_configure(void)
602 struct device_node *np;
605 for_each_matching_node(np, apbuart_match) {
608 const struct amba_prom_registers *regs;
609 struct uart_port *port;
612 ampopts = of_get_property(np, "ampopts", NULL);
613 if (ampopts && (*ampopts == 0))
614 continue; /* Ignore if used by another OS instance */
615 regs = of_get_property(np, "reg", NULL);
616 /* Frequency of APB Bus is frequency of UART */
617 freq_hz = of_get_property(np, "freq", NULL);
619 if (!regs || !freq_hz || (*freq_hz == 0))
622 grlib_apbuart_nodes[line] = np;
624 addr = regs->phys_addr;
626 port = &grlib_apbuart_ports[line];
628 port->mapbase = addr;
629 port->membase = ioremap(addr, sizeof(struct grlib_apbuart_regs_map));
631 port->iotype = UPIO_MEM;
632 port->ops = &grlib_apbuart_ops;
633 port->flags = UPF_BOOT_AUTOCONF;
635 port->uartclk = *freq_hz;
636 port->fifosize = apbuart_scan_fifo_size((struct uart_port *) port, line);
639 /* We support maximum UART_NR uarts ... */
644 grlib_apbuart_driver.nr = grlib_apbuart_port_nr = line;
645 return line ? 0 : -ENODEV;
648 static int __init grlib_apbuart_init(void)
652 /* Find all APBUARTS in device the tree and initialize their ports */
653 ret = grlib_apbuart_configure();
657 printk(KERN_INFO "Serial: GRLIB APBUART driver\n");
659 ret = uart_register_driver(&grlib_apbuart_driver);
662 printk(KERN_ERR "%s: uart_register_driver failed (%i)\n",
667 ret = platform_driver_register(&grlib_apbuart_of_driver);
670 "%s: platform_driver_register failed (%i)\n",
672 uart_unregister_driver(&grlib_apbuart_driver);
679 static void __exit grlib_apbuart_exit(void)
683 for (i = 0; i < grlib_apbuart_port_nr; i++)
684 uart_remove_one_port(&grlib_apbuart_driver,
685 &grlib_apbuart_ports[i]);
687 uart_unregister_driver(&grlib_apbuart_driver);
688 platform_driver_unregister(&grlib_apbuart_of_driver);
691 module_init(grlib_apbuart_init);
692 module_exit(grlib_apbuart_exit);
694 MODULE_AUTHOR("Aeroflex Gaisler AB");
695 MODULE_DESCRIPTION("GRLIB APBUART serial driver");
696 MODULE_VERSION("2.1");
697 MODULE_LICENSE("GPL");